Verilog Instantiation clarification

[bciaren]

In this sample file (from textbook), do these two things mean the same thing?

module eq2(
    input  wire [1:0] a,b,
	 output wire aeqb
	 );
// internal signal declaration
		
	  wire e0,e1;
//body
// instatiate two 1-bit comparators
eq1 eq_bit0_unit(.i0(a[0]), .i1(b[0]), .eq(e0));
eq1 eq_bit1_unit (.eq(e1), .i0(a[1]), .i1(b[1]));

// a and b are equal if individual bits are equal
assign aeqb = e0 & e1;

endmodule

module eq2(
    input  wire [1:0] a,b,
	 output wire aeqb
	 );
// internal signal declaration
		
	  wire e0,e1;
//body
// instatiate two 1-bit comparators
eq1 eq_bit0_unit(.i0(a[0]), .i1(b[0]), .eq(e0));
eq1 eq_bit1_unit (i0(a[1]), .i1(b[1]), .eq(e1));

// a and b are equal if individual bits are equal
assign aeqb = e0 & e1;

endmodule

If not, could you explain why the former is chosen? I'm not following this if that's the case.. thanks

 

[syedshan]

hi

Both are same, will generate exactly the same thing. Just position of the ports connection different
But in the second one there is one error I guess( I have not touched verilog for a long time) as far as I remember you cannot have position and named connection together in the single instance calling.
and if you see in your case you have the two together in the second case

- - - Updated - - -

eq1 eq_bit1_unit (i0(a[1]), .i1(b[1]), .eq(e1));

should be

eq1 eq_bit1_unit (.i0(a[1]), .i1(b[1]), .eq(e1));

 

[mrflibble]

You should use former, because the latter has a big fat error in it. But assuming the error is just a typo as pointed out by syedshan ... then yes they should be equivalent. If you used named port notation a la "eq1 eq_bit1_unit (.i0(a[1]), .i1(b[1]), .eq(e1));" then it should work fine.

Disregarding the missing '.' character, the 2nd version gets my vote. Consistent order of named ports makes it more readable IMO.

 

[bciaren]

YES, it should be:

eq1 eq_bit0_unit(.i0(a[0]), .i1(b[0]), .eq(e0));
eq1 eq_bit1_unit (.i0(a[1]), .i1(b[1]), .eq(e1));

Sorry about that typo! Thank you so much for answering, I hated the way the book wrote it. My book uses the 1st code, I feel the 2nd version is much more easily read.

Thank you again!